From Tokyo to Lisbon
After Germany surrenders, the Soviets keep going, fighting to the English Chanel and tip of Iberia. They also start a communist revolution in Japan as their military pushes to the Pacific. This causes the USA and UK to annex large amounts of territory to combat the Soviets. Eventually, the war became a stalemate by conventional means. The USA attempted to nuke the USSR, however, their bombers were shot down and nukes reverse engineered, resulting in The American West coast and English Chanel being nuked into oblivion. Peace is kept only by the threat of Nuclear Annihilation.